Basic operations and usage of arrays in PHP

Basic operations and usage of arrays in PHP

1. Overview
Array is a very important data type in PHP. It can be used to store multiple values, and can Access these values ​​via index or key. Arrays have rich operations and usage methods in PHP. This article will introduce in detail the basic operations and usage methods of arrays in PHP.

2. Create arrays
In PHP, you can create arrays in two ways: countable arrays and associative arrays.

1. Create a countable array
   A countable array is an array that is arranged in order and indexed numerically. The following is how to create a countable array:

// Method 1: Use the array() function
$numbers = array(1, 2, 3, 4, 5);

// Method 2: Use [] (available from PHP 5.4)
$numbers = [1, 2, 3, 4, 5];

2. Create an associative array
   Associative array is an array stored with string keys and corresponding values. The following is how to create an associative array:

// Method 1: Use the array() function
$student = array("name" => "John", "age" => ; 18, "grade" => "A");

// Method 2: Use [] (available starting from PHP 5.4)
$student = ["name" => "John ", "age" => 18, "grade" => "A"];

3. Accessing array elements
You can access elements in the array through indexes or keys.

1. Accessing countable arrays
   For countable arrays, you can use indexing to access array elements. The index starts from 0 and increases sequentially.

$numbers = array(1, 2, 3, 4, 5);

echo $numbers[0]; // Output 1
echo $numbers[2 ]; // Output 3

2. Accessing associative arrays
   For associative arrays, you can use keys to access array elements.

$student = array("name" => "John", "age" => 18, "grade" => "A");

echo $student["name"]; // Output John
echo $student["age"]; // Output 18

4. Common array operations and functions

1. Get the length of the array
   Use the count() function to get the number of elements in the array.

$numbers = array(1, 2, 3, 4, 5);

echo count($numbers); // Output 5

2. Traverse the array
   PHP provides a variety of methods to traverse the array, the most common method is to use the foreach loop.

$numbers = array(1, 2, 3, 4, 5);

foreach ($numbers as $number) {

echo $number . " ";

}
//Output 1 2 3 4 5

3. Add elements
   You can use the [] or array_push() function to add elements to the array.

$numbers = array(1, 2, 3, 4, 5);

// Use [] to add elements
$numbers[] = 6;

// Use array_push() to add elements
array_push($numbers, 7);

print_r($numbers);
// Output Array (1, 2, 3, 4 , 5, 6, 7)

4. Delete elements
   You can use the unset() function to delete elements in the array.

$numbers = array(1, 2, 3, 4, 5);

unset($numbers[2]);

print_r($numbers );
// Output Array (1, 2, 4, 5)

5. Summary
This article introduces the basic operations and usage of arrays in PHP, including creating arrays and accessing array elements , get the array length, traverse the array, and add and remove elements. Arrays are a very important data type in PHP and are often used in actual development. Mastering the basic operations and usage of arrays can help developers process data more flexibly and efficiently.

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